When communicating devices communicate each other, it is a common practice to authenticate each other for that one communicating device confirms the other communicating device.
For example, a transmitter generates an authenticator based on data and a secret key and transmits the data with the authenticator. A receiver verifies whether the authenticator added to the data is valid or not using a secret key or a public key and judges whether the data transmitted by a valid device using a verification result.
In an authentication method using the authenticator or a digital signature, if an attack that attackers transmits many packets to a receiving apparatus is executed, normal communication is disturbed by increasing authentication processing in the receiving apparatus.
Therefore, there is a fast authentication method that processes authentication fast in TCP layer in addition to an authentication in application layer.
The fast authentication method prevents the normal communication disturbed by suppressing to increase authentication processing.